EXHIBIT31.1

CERTIFICATIONS

I, Michael A. McManus, Jr.,certify that:

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| 1.  | I have reviewed thisquarterly report on Form 10-Q of MISONIX,INC. |

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| 2.  | Based on my knowledge, thisreport does not contain any untrue statement of a material fact or omitto state a material fact necessary to make the statements made, inlight of the circumstances under which such statements were made, notmisleading with respect to the period covered by this report; |

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| 3.  | Based on my knowledge, the financialstatements, and other financial information included in this report,fairly present in all material respects the financial condition,results of operations and cash flows of the registrant as of, and for,the periods presented in this report; |

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| 4.  | The registrant's othercertifying officer(s) and I are responsible for establishing andmaintaining disclosure controls and procedures (as defined in ExchangeAct Rules 13a-15(e) and 15d-15(e)) [*** Omitted pursuant toextended compliance period] for the registrant and have: |

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|  | (a)  | Designed such disclosure controlsand procedures, or caused such disclosure controls and procedures to bedesigned under our supervision, to ensure that material informationrelating to the registrant, including its consolidated subsidiaries, ismade known to us by others within those entities, particularly duringthe period in which this report is being prepared; |

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|  | (b)  | [*** Omitted pursuant toextended compliance period]; |

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|  | (c)  | Evaluated the effectiveness of theregistrant's disclosure controls and procedures and presented inthis report our conclusions about the effectiveness of the disclosurecontrols and procedures, as of the end of the period covered by thisreport based on such evaluation; and |

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|  | (d)  | Disclosed in this report any changein the registrant's internal control over financial reportingthat occurred during the registrant's most recent fiscal quarter(the registrant's fourth fiscal quarter in the case of an annualreport) that has materially affected, or is reasonably likely tomaterially affect, the registrant's internal control overfinancial reporting; and |

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| 5.  | Theregistrant's other certifying officer(s) and I have disclosed,based on our most recent evaluation of internal control over financialreporting, to the registrant's auditors and the audit committeeof the registrant's board of directors (or persons performing theequivalent functions): |

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|  | (a)  | Allsignificant deficiencies and material weaknesses in the design oroperation of internal control over financial reporting which arereasonably likely to adversely affect the registrant's ability torecord, process, summarize and report financial information; and |

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|  | (b)  | Any fraud, whether or not material,that involves management or other employees who have a significant rolein the registrant's internal control over financialreporting. |

Date: November 14, 2005

|  | /s/ Michael A. McManus,Jr. |
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|  | Michael A.McManus, Jr. President and Chief ExecutiveOfficer |
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